ID Mismatch

Old video, New course

The first of many adaptations for ELAT! This was not necessarily a change on the data, but a situation that was not foreseen during development: some courses have many life cycles! This means that some course elements (like videos or quizzes) will have very similar ids, which can cause a mismatch when processing a course that has run in previous editions. Discovered and fixed 20/05/2019

If you remember the process pipeline, once the metadata is processed, ELAT will check every log record for the current course id, to avoid unnecessary processing for records of other courses. The initial implementation, however, was only tested with courses that were first of their series, so there was never a case where one of the courses had already happened. With further evaluation, it was discovered that the course id, for example FP101x or EX103x, was present in records from the 2015, 2016 and 2017 editions. Since some courses allow to be self-paced, it can happen that students were enrolled in a previous edition, and their interaction records appear in logs together with the records of students in the latest edition.

Discovery

While testing some indicators, it was necessary to check the number of times students were interacting with the course material. For this, ELAT would use the course elements extracted from the metadata, and compare them with the corresponding sessions using the element id. Some sessions were interacting with elements that did not exist in the database, which caused an error in the processing of the indicator. Those non-existent ids were dated for previous years.

Fix

The easiest way to fix this is by expanding the course id to include the edition, so FP101x is now FP101x-3T2015 and EX103x is EX103x-2T2016. All course elements contain this longer identifier and checking for this compared to the short version caused no issues in the performance or results of ELAT.